Master of Science / Biochemistry and Molecular Biophysics Interdepartmental Program / Anna Zolkiewska / Cellular senescence is a state of irreversible cell cycle arrest in response to non-lethal stress. In cancer cells, senescence can be induced by chemotherapy, radiation, or signals from the tumor microenvironment, such as transforming growth factor β (TGFβ). Senescent cells are metabolically active and have altered gene expression compared to their non-senescent counterparts. Senescent cells release a wide variety of factors, including extracellular domains of transmembrane proteins that require proteolytic cleavage by specific proteases. ADAMs (A Disintegrin and Metalloprotease domain-containing proteins) are enzymes that cleave many transmembrane proteins, such as growth factor precursors or adhesion molecules, and thus may act as sheddases in senescent cells. Here, we investigate ADAM expression levels during TGFβ- induced cellular senescence. SUM149PT and SUM102PT breast cancer cells were incubated with TGFβ, followed by treatment with high doses of paclitaxel to remove actively proliferating, non-senescent cells. Induction of cellular senescence was examined by evaluating changes in cell size and granularity, and by β-galactosidase staining. ADAM mRNA levels were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Among several ADAMs tested, ADAM12 mRNA was significantly upregulated in senescent cells. In addition, we demonstrated that ADAM12 knock-down leads to decreased activation of epidermal growth factor receptor (EGFR), an important modulator of cancer cell growth, survival, and metastasis. This effect of ADAM12 knock-down was likely due to a diminished release of soluble EGF or EGF-like ligands from cells. Since senescent cells often release increased amounts of these ligands, ADAM12 may modulate the senescence secretome in senescent breast cancer cells.

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Thesis advisor: Robert Ross / Thesis advisor: Timothy Crawford / This paper examines the credibility issue in China's extended deterrent attempts during the Cold War. In its efforts to protect North Korea, North Vietnam and Kampuchea, how did China convey its threats, and why did these initiatives have differing results? First, I argue that signaling is the key explaining credibility of China's extended deterrent threats across space and time. While ambiguous signals ruined China's credibility in deterring challenges on North Korea and Kampuchea, clear-cut signals backed threats in China's attempts to save North Vietnam. Consequently, China's signals in the first two cases were disregarded or misunderstood but were perceived as expected in the last case. Secondly, the paper seeks to appraise the explanatory power of current theoretical approaches with regard to the effectiveness of extended deterrent threats. Balance of interests (BOI) and Balance of Capabilities (BOC) shed lights on sources of deterrence outcomes, but neither of them is sufficient to explain the cases. The paper concludes that China's peaceful rising is more likely if Beijing signals its interests and capabilities more clearly. / Thesis (MA) — Boston College, 2011. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Political Science.

[pt] O design de sinalização no Brasil: a introdução de novos conceitos de 1970 a 2000, retrata a construção do conceito de design de sinalização, a partir da observação das mudanças ocorridas na estruturação do briefing e no processo de design em projetos brasileiros, no período de 1970 a 2000. A introdução de novos requisitos e conceitos no seu desenvolvimento foi observada considerando: o ambiente físico do projeto e do mercado; a especificação, a elaboração do briefing e os elementos adotados na especificação dos projetos; o gerenciamento do projeto; os conceitos e as teorias utilizadas no seu desenvolvimento, assim como as interfaces com outras disciplinas. Através de entrevistas realizadas com designers experientes, atuantes no mercado de trabalho, e que têm projetos expressivos na área do design de sinalização, retrata-se a sua trajetória e a quebra de paradigmas ocorrida neste período. / [en] Signage design in Brazil: the introduction of new concepts between the years 1970 and 2000 presents the construction of a concept of signage design from the point of view of the changes occurred between 1970-2000. The structuring of the briefing, the process of design, and its project and results. The introduction of new postulates and concepts in its development taking into account the physical and spatial ambiences, the project and the market were observed considering: the elaboration of the briefing and the evaluation of relevant elements to the projects. The management of the project: the concepts and theories employed in the development of a project, the multidisciplinarity.Through interviews with expert designers, with vast experience in this market and well known projects in signage design we have meant to present the course signage design has taken and the paradigm ruptures that have occurred throughout these years.

Thesis advisor: Marc-Jan Gubbels / Toxoplasma gondii – an obligate intracellular parasite – has a complex multistep mechanism for host cell invasion with a pivotal role played by calcium signaling. However, the coordination amongst the players in all the key steps of this signaling pathway, essential for parasitic life cycle of Toxoplasma, is still not entirely known. Given the evolutionary relationship between ciliates and apicomplexans, this work evaluates the functions of three orthologous proteins in cell signaling of alveolates leading to calcium-dependent exocytosis of vesicles such as trichocysts and micronemes. The proteins investigated are calmodulin (CaM) which is a calcium sensor, calcineurin (CN), a protein phosphatase, and parafusin-related protein 1 (PRP1), the Toxoplasma ortholog of ciliate protein parafusin. In the ciliate, CaM activates CN upon rise in intracellular calcium. Activated CN then leads to the dephosphorylation of the secretory vesicle scaffolding protein called parafusin. Parafusin dephosphorylation dissociates it from the calcium-dependent secretory vesicles, which then discharge their contents. As expected upon conditional depletion, we found CaM to be essential for Toxoplasma tachyzoites and CN to be significant for the lytic cycle. Surprisingly, the microneme secretion remained normal in the CN depleted parasites, although there was significant reduction in the attachment of the parasite to the host cell. We also found that PRP1 is dispensable for Toxoplasma lytic cycle, despite its absence affecting the microneme secretion induced by the calcium ionophore, A23187. However the secretion defect is not uniform and remains comparable to the wild type when it is induced using other pharmacological agents like ethanol, zaprinast and propranolol. Therefore despite phylogenetic conservation of the three proteins in alveolates, this work demonstrates their involvement in distinct functional aspects in Toxoplasma compared to other ciliates. Alongside the limited understanding of the molecular mechanism, our knowledge about the cellular sensors in Toxoplasma is also scarce. Our laboratory has previously identified a double C2 (DOC2) domain containing protein called TgDOC2 and demonstrated its role in overall microneme secretion. However, TgDOC2 does not regulate the dosed microneme release associated with varied steps of the egress-invasion trajectory. In general, DOC2 domain containing proteins work in coordination with each other to execute their cellular function, mostly in calcium-dependent manner. We therefore, wanted to expand our knowledge of this domain containing proteins in the parasite. In this work, we investigated a conserved apicomplexan protein called FER2 containing multiple DOC2 domains. Conditional depletion of FER2 appeared detrimental due to significant loss of invasion and attachment of the parasites. FER2 depleted parasites have normal microneme secretion, which is currently the only known calcium-dependent secretory organelle in Toxoplasma, but abrogated the release of rhoptries, the second secretory organelle to be released during invasion. Altogether this work extends the importance of calcium signaling in Toxoplasma gondii and brings into light the novel aspects of some parasitic proteins which are significant in reconstructing our understanding of the signaling pathway in this parasite. / Thesis (PhD) — Boston College, 2016. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology.

Thesis advisor: Charles Hoffman / The fission yeast Schizosaccharomyces pombe senses environmental glucose through a cAMP-signaling pathway. Elevated cAMP levels activate protein kinase A (PKA) to inhibit transcription of genes involved in sexual development and gluconeogenesis, including the fbp1⁺ gene, which encodes fructose-1,6-bisphosphatase. Glucose-mediated activation of PKA requires the function of nine git genes (git=glucose insensitive transcription), encoding adenylate cyclase, the PKA catalytic subunit and seven “upstream” proteins required for glucose-triggered adenylate cyclase activation. This thesis describes the cloning and characterization of the git10⁺ gene, which is identical to swo1⁺ and encodes the S. pombe Hsp90 chaperone protein. This discovery is consistent with the previous identification of the Git7 protein as a member of the Sgt1 Hsp90 co-chaperone family. Glucose repression of fbp1⁺ transcription is impaired by both hsp90⁻ and git7⁻ mutant alleles, as well as by chemical inhibition of Hsp90 activity and temperature stress. Unlike the swo1⁻ and git7⁻ ts mutant alleles, the git10-201 allele and git7-93 allele support cell growth at 37º and show no cytokinesis defect, while severely reducing glucose repression of an fbp1-lacZ reporter, suggesting a separation-of-function defect. A physical interaction between Git7 and Hsp90 in S. pombe was also detected and findings in this thesis suggest their involvement in the initial assembly of the cAMP complex. / Thesis (PhD) — Boston College, 2008. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology.

by Wong, Wan-Lung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 88-92). / Abstract also in Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Mobile Agent Systems --- p.1 / Chapter 1.2 --- Distributed Control Systems --- p.2 / Chapter 1.3 --- Motivation of the Dissertation --- p.3 / Chapter 1.4 --- Related Work --- p.3 / Chapter 1.5 --- Overview of the Dissertation --- p.5 / Chapter 2 --- Mobile Agents --- p.6 / Chapter 2.1 --- Definition of an Agent --- p.7 / Chapter 2.1.1 --- A Weak Notion of Agents --- p.8 / Chapter 2.1.2 --- A Stronger Notion of Agents --- p.9 / Chapter 2.1.3 --- Other Attributes of Agents --- p.9 / Chapter 2.2 --- Characteristics of Mobile Agents --- p.10 / Chapter 2.3 --- Programming Languages for Mobile Agents --- p.11 / Chapter 3 --- A Mobile Agent Framework --- p.16 / Chapter 3.1 --- The Framework --- p.16 / Chapter 3.1.1 --- Agent Operations --- p.19 / Chapter 3.1.2 --- Agent Life Cycle --- p.23 / Chapter 3.1.3 --- Agent Migration Server --- p.26 / Chapter 3.1.4 --- Communication Server --- p.28 / Chapter 3.1.5 --- Facilitator --- p.30 / Chapter 3.2 --- April as a Mobile Agent Language --- p.30 / Chapter 4 --- An Agent Based Distributed Train Control and Monitoring Sys- tem --- p.32 / Chapter 4.1 --- Introduction to DiTCAMS --- p.33 / Chapter 4.2 --- Terminology in DiTCAMS --- p.34 / Chapter 4.3 --- Architecture of DiTCAMS --- p.34 / Chapter 4.3.1 --- Active Agents --- p.36 / Chapter 4.3.2 --- Passive Agents --- p.38 / Chapter 4.4 --- Agent Collaborations --- p.41 / Chapter 4.4.1 --- Track Resource Allocation --- p.41 / Chapter 4.4.2 --- Sensor Triggering --- p.42 / Chapter 4.4.3 --- Hardware Control --- p.42 / Chapter 4.4.4 --- Train Migration --- p.42 / Chapter 4.5 --- Other Implementation Issues --- p.46 / Chapter 4.5.1 --- Track Resource Management --- p.47 / Chapter 4.5.2 --- Railway Topology Encoding --- p.50 / Chapter 4.5.3 --- Train Location Determination --- p.54 / Chapter 4.5.4 --- Train Speed Control --- p.62 / Chapter 4.5.5 --- Collision Prevention and Recovery --- p.64 / Chapter 4.5.6 --- Improving Efficiency of April for Real-time Execution --- p.65 / Chapter 5 --- Discussions --- p.72 / Chapter 5.1 --- On Enabling Mobile Agents --- p.72 / Chapter 5.2 --- Cost in Achieving Mobile Agents --- p.74 / Chapter 5.3 --- On Using April as a Mobile Agent Language --- p.75 / Chapter 5.4 --- History of DiTCAMS --- p.76 / Chapter 6 --- Concluding Remarks --- p.79 / Chapter 6.1 --- Contributions --- p.79 / Chapter 6.2 --- Limitations --- p.80 / Chapter 6.3 --- Future Work --- p.81 / Chapter A --- Hardware Components --- p.83 / Chapter B --- A Concurrent Administrator Based Train System Using C --- p.85 / Bibliography --- p.88

The calorie restriction (CR) and insulin/IGF-I-like signalling (IIS) are two pathways regulating the lifespan of C. elegans. Recent studies showed that glucose restriction extends the lifespan of C. elegans while excessive glucose shortens the lifespan of the worms. The first step of the glucose metabolism is the transport of glucose across the plasma membrane by the glucose transporters. The work described in this thesis aims to identify glucose transporters in C. elegans and to provide a primary investigation of the in vitro and in vivo function of the identified glucose transporter. Nine putative transporters have been cloned and expressed. Out of the nice cloned putative transporters in the C. elegans genome, H17B01.1 (H17) only is identified as a fully functional glucose transporter using an oocyte expression system in which glucose transport activity is directly measured. The two transcripts of H17 are both capable of transporting glucose with high affinity, as well as transporting trehalose. Heterologous expression of H17 in mammalian CHO-T cells suggests that the protein is localised both on the plasma membrane and in the cytosol. In vitro studies of H17 show that the protein does not respond to insulin stimulation when expressed in mammalian CHO-T cell and rat primary adipocyte systems. In vivo functional studies using H17 RNAi indicate that the worm’s lifespan is not affected by the H17 knockdown. However, glucose metabolism of C. elegans (as measured by glucose oxidation to CO2 and incorporation into fat reserves) is influenced by the decreased expression of H17, especially in the daf-2 mutant strain, e1370. However, the increase of glucose metabolism caused by H17 knockdown observed in daf-2 mutant is inhibited in the age-1 and akt-1 mutant strains. The findings reported in this thesis suggest that the H17 glucose transporter may play an important role glucose metabolism in C. elegans and that this transport and metabolism is influenced by insulin receptor activity and serine kinase cascades.

Tissue cells exhibit varying responses according to the stiffness of their extracellular matrix (ECM). The mechanism of this stiffness sensing is not fully understood; however, it is known that cells probe stiffness by applying intracellular force to the ECM via integrin-mediated focal adhesions. The bonds between integrins and ECM have been described as “catch bonds�, and it is unclear how ECM viscoelasticity affects these bonds. We have observed the effects of ECM stiffness on the binding strength of integrins to ECM ligands by measuring the dissociation force of individual integrin-ligand bonds of 3T3 fibroblasts on collagen-coated polyacrylamide gels using atomic force microscopy. Results show that integrins exhibit higher rates of activation on stiff substrates. Furthermore, increased matrix stiffness results in the occurrence of larger, multi-bond dissociation events, which suggests that substrate stiffness may affect the cellular response by promoting integrin clustering as well as by modulating the maximum possible force between individual integrins and the ECM.